Reaction product of a diisocyanate and an alkyl amine salt of an alkyl amide of alkyl ortho phosphoric acid and lubricating oil thickened with same



United States Patent REACTION PRODUCT OF A DIISOCYANATE AND Thisinvention relates to new additive agents for high temperature lubricantsand grease compositions containing the same. More particularly thisinvention pertains to compositions of matter suitable for use asgelation or thickening agents in thermally stable greases for use underhigh temperature conditions and greases thickened with the same.

As lubricating greases are required for use at higher and highertemperatures because of increased speeds of engines and'machines, theadvent of jet propulsion, atomic energy as a power source, etc. it'hasbecome increasingly difficult to prepare greases fulfilling suchrequirements. In attempting to provide high temperature greases the arthas progressed from the use of petroleum lubricant vehicles thickenedwith metal soaps of long chain fatty acids, eg. lithium hydroxystearate, to more thermally stable synthetic lubricating oils such asthe aliphatic diesters of dicarboxylic acids, silicone polymers, etc.,thickened with soaps or inorganic materials such as silica gels. Themore thermally stable oleaginous lubricant vehicles developed in recentyears are able to withstand high working temperatures because of theirthermal stability and relatively low volatility. However, the progressof grease thickener research has not in general kept pace with thedevelopment of lubricant vehicles. At temperatures as high as 400-450?F. there are few, if any, greases available which will retain theirconsistency for a substantial period of time. a

I have found certain new compositions which are useful as greasethickeners in lubricant oils and which provide a high degree of thermalstability to greases, thereby allowing them to retain their consistencyat temperatures Such alkyl amine salts have the following formula:

Wherein the R's are aliphatic hydrocarbon substituents having from about8 to about 20 carbon atoms and preferably from about 12 to about 18carbon atoms and R is an organic water solubilizing substituent such asan alkyl radical having less than carbon atoms, an alcohol ora glycerol.vention are those disclosed by W. H. Woodstock in US. Patent 2,406,423.The preparation of the alkyl amine salts may be by the method thereindisclosed by Woodstock. Of particular preference are the commerciallyprepared salts such as, for example, Victamine C, Victamine D, VictamineG, and Victamine K as produced by the Victor Chemical Works. Victamine Cis the lauryl amine salt of the lauryl amide of ethyl orthophosphoricacid and Victamine G is an analogue of Victamine C. Victamine D is thestearyl amine salt of the stearyl amide of ethyl orthophosphoric acidand corresponds to the above formula wherein the R's are stearyl groupsand R is ethyl. Victamine K is an analogue .Qf-ffVictami e i a d is p pfrom a ture of predominantly saturated C primary amines so,

3,002,928 Patented Oct. 3, 1961 2 that the R's of the above formulacorrespond to saturated C groups while R represents ethyl.

The diisocyanates which are used to react with the alkyl amine saltsabove to'form the reaction products of the invention are those compoundswhich have at least 2 isocyanate radicals. Examples of suitablediisocyanates are toluene diisocyanate, p,p'-diisocyanate biphenyl, 1,4diisocyanate benzene, p,p diisocyanate diphenylmethane, 1,6 diisocyanatehexane, 1,12 diisocyanatedodecane, 1,3,S-benzene-triisocyanate,naphthylene diisocyanate, bitolylene diisocyanate,tIis-p-isocyanatephenylmethane, etc.

The reaction products of this invention are prepared by admixing thealkyl amine salt? with an oleaginous lubricant vehicle or solvent ordiluent and slowly heating the mixture to a temperature above about 100F., advantageously in the range of about 150 F. to about 450 F. andpreferably in the range from about 200 F. to about 350 F. and thenadding about 0.5 to about 2.0 and preferably from about 0.8 to about 1.2moles of the diisocyanate per mole of salt; The reaction mixture ismaintained within the above temperature range until the reaction iscomplete. The reaction proceeds rapidly within a short period of time.We have found that 10 minutes is usually suflicient within the preferredreaction temperature range; however, much longer reaction times must beused if needed. The reaction mixture is then cooled and milled.

Although I do not wish to be held to any theories regarding the reactionbetween an alkyl amine salt of an alkyl amide of alkylorthophosphoricacid and a diisocyanate I believe that the reaction is explained by thefollowing typical example: approximately equimolar amounts of bitolylenediisocyanate and the lauryl amine salt of the lauryl amide of methylorthophosphaft e are charged to a solvent extracted mineral lubricatingoil in as high as about 250 to about 450 F. In accordance" with thepresent invention the new compositions of mata reaction vessel andheated to about 150 F. for 10 minutes. A mixture of reaction products ofunknown structure is formed. Although the structures of the products arenot known, it is believed the reaction proceeds in two steps to formproducts which may resemble those structures set out below. In the firststep, it is believed that the amine salt of the lauryl amide of methylorthophosphate may decompose into a primary amine and a The alkyl aminesalts useful within this inphosphate ester with an acidic OH group asfollows:

In the second step, the primary amine and the phosphate ester may thenreact with the two'isocyanate groups of the bitolylene diisocyanate toform a mixture of products such as those shown by the unbalancedequation below:

CHaO

iJEa JHa HO OH The reaction is advantageously carried out in thepresence of a sufficient amount of an oleaginous lubricant vehicle toform a thickened grease containing from about 2 to about 25, andpreferably from about 5 to about weight percent of the reaction productthickening agent. Therefore, from about 75 to about 98, and preferablyfrom about 85 to about 95, weight percent of an oleaginous lubricantvehicle is advantageously used in the reaction mixture.

Oleaginous lubricant vehicles which can be used in accordance with thisinvention to form grease products can be silicone polymer oils, minerallubricating oils, synthetic hydrocarbon lubricating oils, syntheticlubricating oils such as polyalkylene glycols and their derivatives,high molecular weight esters of dicarboxylic acids, polyfluoroderivatives of organic compounds such as the trifiuorovinyl chloridepolymers shown as Fluorolube (made by Hooker Chemical Company), thetrifluoroethylene polymers, and other lubricant vehicles.

The silicone polymer oils which may be employed in accordance with thepresent invention are those falling substantially within the lubricatingoil viscosity range. In general, such oils have the following unitstructure:

wherein R and R represent substituted or unsubstituted alkyl, aryl,alkylaryl, arylalkyl or cycloalkyl radicals.

Such compounds may be produced by well-known meththe lubricating oilviscosity range are suitable, these gen erally possessing a viscosity at100 F. which is within the range of from about 25 to about 3500 S.S.U.It is preferred, for purposes hereof, to employ such 'oils as have aviscosity at'100 F. of from about 100 S.S.U. to about 1250 S.S.U. Suchproducts are generally colorless and inert, have a very low volatilityand undergo relatively slight change in viscosity for a given change intemperature. Relatively common oils of this type are dimethylsiliconepolymer, phenylmethylsilicone polymer, chlorophenylmethylsiliconepolymer, etc., it being preferred to employ either thephenylmethylsilicone or the chlorophenylmethylsilicone polymer inaccordance herewith. Methods of preparing such compounds are taught innumerous patents, e.g. US. 2,410,346, US. 2,456,496, and in theliterature such as Chemistry of the Silicones by Rochow, page 61, etseq. A particularly desirable .phenylmethylsilicone polymer for use inaccordance with the present invention is Dow-Corning 550 Silicone Fluid,

a product of Dow-Corning, Inc., which has a Saybolt Universal viscosityat 100. F. of about 300 to about 400 seconds. Another suitable siliconepolymer is a chlorosirable to produce such phenylmethylsilicone marketedas GE 81406 by General Electric Company.

Other oleaginous vehicles which may be empolyed herewith are, forexample, mineral oils in the lubricating oil viscosity range, i.e. fromabout 50 S.S.U at F. to about 300 S.S.U at 210 F. These mineral oils arepreferably solvent extracted, to substantially remove the low V.I.constituents, e.g. aromatics, with phenol, furfural,B,B'-dichlorodiethylether (Chlorex), liquid S0 nitrobenzene, etc.Synthetic lubricating oils resulting from polymerization of unsaturatedhydrocarbons or other oleaginous materials within the lubricating oilviscosity range such as high molecular weight polyoxyalkylene compoundssuch as polyalkylene glycols and ethers and esters thereof, aliphaticdiesters of dicarboxylic acids such as the butyl, hexyl, 2-ethylhexyl,decyl, lauryl, etc. esters of sebacic acid, adipic acid, azelaic acid,etc. may be thickened by the reaction products of the present inventionto produce excellent greases. Polyfluoro derivatives of organiccompounds, particularly hydrocarbons, and dibacic acid esters of H(CF,CH OH, in the lubricating oil viscosity range can be thickened with compounds of the present invention. Other synthetic oils, such as esters ofaliphatic carboxylic acids and polyhydric alcohol, e.g.trimethylolpropane pelargonate, pentaerythritol hexanoate, can be usedas suitable oil vehicles. Where the grease product is to be employedunder high temperature conditions lubricating oils which are stable,i.e. do not decompose, at the temperatures to be encountered should beused as the lubricant vehicle. For such uses, it is preferred to useoils such as silicone polymers, fluorocarbons and the like.

Rather than preparing the grease thickeners of this invention ascomponent parts of a thickened grease, it may be desirable to preparegrease thickener addition agents. Such addition agents are readilyprepared by using a solvent or diluent which is capable of being removedafter the reaction in lieu of using the oleaginous lubricant vehiclerecited above. After the reaction, the solvent or diluent is removedleaving the thickening agent. Such addition agents may also be preparedfrom the above prepared thickened greases; accordingly, the thickenedgrease prepared above is washed with a solvent such as hexane or heptaneto remove the lubricating oil leaving the reaction product as aninsoluble. It may be dethickening agents with the oleaginous lubricantvehicle removed for purposes of storing, such as where space is limited.The addition agents may then later be added to oleaginous lubricantvehicles in amounts of about 2 to about 25 weight percent and preferablyfrom about 5 to about 15 weight percent to form a finished grease.

Also concentrates of greases containing the grease thickener may beformed by reducing the amount of oleaginous lubricant vehicle in thereaction mixture to provide a thickener concentration within the rangeof from about 25 to about 65 weight percent of the total reactionmixture. If the reaction mixture is too thick for convenient handling, asuitable solvent or diluent may be added and later removed after thereaction. Such V concentrates of greases may be used to prepare greasecompositions containing the amounts of thickener set out abovebydilution of the concentrate with an oleaginous lubricant vehicle.

The grease products containing the grease thickener and concentratesthereof can contain one or more well known addition agents suitableunder the conditions of use to impart desired properties thereto, suchas, by way of example, antioxidants, extreme pressure agents, corrosioninhibitors, anti-leak agents, anti-foam agents, graphite, molybdenumsulfide, etc.

To further illustrate this invention the following specific examples ofthickened grease compositions were prepared and tested as indicatedbelow for suitability of use at high temperatures.

.. .Examplel.

4.5 g. of Victamine K were admixed with 935g. of a phenol extracted SAE40 mineral lubricating oil. The mixture was slowly heated in a reactionVessel toa tem-' perature ranging from 300 to 310 F. and 2.0 g. ofbitolyl ene diisocyanatewere added. The reaction mixture'was maintainedat a temperature rangingi'rom'300 to 310 F. for about minutes. Theresulting material was cooled and milled to produce a finished greaseproduct.

Example 2 4.0 g. of -Victamine K were admixed with 94.0 g. ofDow-Corning Silicone Oil 550. The mixture was slowly heated in areaction vessel to a'temperature ranging from 300 to 310 F. and 2.0 g.of bitolylene diisocyanate were added. The reaction mixture wasmaintained at'a temperature ranging irom300 to 310 F. for about 10minutes; The resulting material was cooled and milled to produce afinished grease product.

Example 3 5.0 g. of Victamine K were admixed with 93.0 g. of a phenolextracted SAE 40 mineral lubricating oil. The mixture was slowly heatedin a reaction vessel to a temperature ranging from 300 to 310 F. and 2.0g. of bitolylene diisocyanate were added. The reaction mixture wasmaintained at a temperature ranging from 300 to 310 F. for about 10minutes. The resulting material was cooled and milled to produce afinished grease product.

Example 5 7.0 g. of Victamine C were admixed with 85 g. of diethyl hexylsebacate. The mixture was slowly heated in a reaction vessel to 300 F.and 8.0 g. of bitolylene diisocyanate were added. The reaction mixturewas maintained at a temperature of about 300 F. for five minutes. Theresulting mixture was cooled and milled to produce a finished greaseproduct.

Example 6 11.6 g. of Victamine C were admixed with 85 g. of trimethylolpropyl pelargenate. The mixture was slowly heated in a reaction vesselto 300 F. and 3.4 g. of bitolylene diisocyanate were added. The reactionmixture was maintained at a temperature of about 300 F. for fiveminutes. The resulting mixture was cooled and milled to produce afinished grease product.

Example 7 4.9 g. of Victamine D and 93.0 g. of a phenol extracted SAE 40mineral lubricating oil were mixed in a beaker. The mixture was heatedto 310 F. 2.1 g. of bitolylene diisocyanate were then added and thereaction mixture was held at about 310 F. for 5 minutes. The resultingmixture was cooled and roll milled to produce a finished grease product.

Example 8 4.9 g. of Victamine D and 93.0 g. of a phenol extracted SAE 40mineral lubricating oil were mixed in a beaker. The mixturewas heated to200 F. and 2.1 g. of bitolylene diisocyanate were added. The reactionmixture was held at about 200 F. for 5 minutes, cooled and roll milledto produce a finished grease product.

The unworked and worked penetration values for the two ASTMtests arereported in Table 1.

TABLE 1 Unworked Worked Drop I Example Penetra- Penetra- Point,F.-

' h, A tion tion 1 Penetrations determined on a 54 size cone andconverted.

The only slight variationsbetween unworked penetration and workedpenetration in the above tests demonstratesthe consistency of thegreases herein-above described The high drop points obtained demonstratethe suitability of such greases for use at temperatures even upto.about450 F. It is evident. from the above disclosure andillustrations that I have provided grease thickening agents, thickened-greasejcompositions anda method for their preparation, which thickenedgrease compositions have excellent penetration characteristics and ahigh drop point enabling their use. ,for excellent, lubrication atelevated temperatures.

Therefore, I claim: 1 p

1. As a composition of matter, the product obtained by reacting at atemperature in the range between about F. and about 450 F. from about0.5 to about 2.0 moles of an organic diisocyanate with one mole of acompound corresponding to the formula:

wherein R is an alkyl radical having from about 8 to about 20 carbonatoms and R is a water solubilizing radical.

2. The composition of claim 1 wherein said diisocyanate and saidcompound are reacted in a mole ratio of from about 0.8:1.0 to about12:10, diisocyanate: said compound.

3. The composition of claim 1 wherein the diisocyanate is bitolylenediisocyanate and R has from about 12 to about 18 carbon atoms.

4. The composition of claim 3 wherein R has 12 carbon atoms.

5. The composition of claim 3 wherein R has 18 carbon atoms.

6. As a composition of matter, the lubricating grease product obtainedby reacting an alkyl amine and a compound corresponding to the formula:

0B R--N-P -0 011 wherein R is an alkyl radical having from 8 to about 20carbon atoms and R is a water solubilizing radical selected from theclass consisting of an alkyl radical having less than 5 carbon atoms, analcohol and a glycerol with an organic diisocyanate at a temperature, inthe range of from about F. to about 450 F. in the presence of a normallyliquid oleaginous lubricant vehicle for a period of time suificient toform a reaction product of said alkyl amine and said compound with saiddiisocyanate in said oil.

7. The composition of claim 6 wherein said reaction product constitutesfrom about 2 to about 25 weight percent of the composition.

'8. The composition of claim 6 wherein said normally licprid oleaginonslubricant vehicle is an ester lubricating fluid.

9. The composition-of olaim'6 wherein said diisocyanate and said compondare in a molar ratio of irom about 08:10 to about 1 241.0, diisocyanate:said compound.

10. The composition of claim 6 wherein the organic diisocyanate .isbitolyle'ne diisocyanate.

11. The compositionof claim 10 wherein R has 12 carbon atoms.

12. The composition of claim l0-wherein R has '18 carbon atoms. 7 V 13.As a composition of matter, the lubnicatinggrease concentrate obtainedby reacting with a normally liquid oleaginous lubricant vehicleacompouud corresponding to the formula:

wherein .R is an :alkyl radical :having from about Soto about carbonatoms and R is a water solubilizing alkyl radical having from 1 to 4carbon atoms inclusive with an organic diisocyanate at a temperature inthe range of from about 200 F. to about 350 Etc obtain a reactionproduct of. said compound and said tdiisocyanate in said oil, whereinthe mole ratio of said diisocyanate to said compound in fromfi0.8: 1.0to about 1.2: 1.0 and the tot-alweight of said reaction product isfromabout weight percent to about weight percent of the totalcomposition.

14. The composition of claim 13 wherein said oil is a siliconelubricating oil.

15. The method of thickening lubricating oils to form lubricating greasecompositions having excellent consistency and. high temperature droppoint properties, which method comprises admixing with a normally liquidlubricating ,a compound corresponding to the formula:

H 0R1 R-NP O ONHgR wherein R is an 'alkyl radical having from about 8 toabout 20 carbon atoms and R is a water solubilizing group, subjectingthe resulting mixture to a temperature in the range of from about F. toabout 450 E; adding from about 0.5 to about 2.07moles of an organicdiisocyanate to said mixture per mole of said compound, mainaining theresulting reaction mixture at .a tempera-v ture in the .range of fromabout 100 F. to about 450". ;F. for a period of time suflicient to forma reaction product of said compound with said diisocyanate in said oil,cooling said reaction product in said oil, and milling said reactionproduct in said oil whereby said lubricating g grease composition isformed.

References Cited in the file of this patent UNITED STATES PATENTSWoodstock Aug. 27,4946 Norton et a1 Aug. 4, 1959 D UNITED STATES PATENT.OFFICE WYYSEAL) CERTIFICATE OF CORRECTION Patent Nos, 30O2 928 October 31 961 Steplnerrfi Zajac It is hereby certified that error appears in theabove numbered patent requiring correction and that the said LettersPatent should read as corrected below. v Y

C0lumn"7, line 28 for -"in.".- read is;

r Signed and. sealed this 3rd day of April 1962.,

At test:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissior er 0t Paten"

6. AS A COMPOSITION OF MATTER, THE LUBRICATING GREASE PRODUCT OBTAINEDBY REACTING AN ALKYL AMINE AND A COMPOUND CORRESPONDING TO THE FORMULA: